From patchwork Fri Dec 3 10:42:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 12654769 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 181DDC433EF for ; Fri, 3 Dec 2021 10:43:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380086AbhLCKqp (ORCPT ); Fri, 3 Dec 2021 05:46:45 -0500 Received: from foss.arm.com ([217.140.110.172]:46994 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379967AbhLCKqf (ORCPT ); Fri, 3 Dec 2021 05:46:35 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AB53E1570; Fri, 3 Dec 2021 02:43:11 -0800 (PST) Received: from a077416.arm.com (unknown [10.163.33.180]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5DCFB3F5A1; Fri, 3 Dec 2021 02:43:07 -0800 (PST) From: Amit Daniel Kachhap To: linux-kernel@vger.kernel.org Cc: Christoph Hellwig , Vincenzo Frascino , Kevin Brodsky , linux-fsdevel , kexec , Amit Daniel Kachhap , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86 Subject: [RFC PATCH 05/14] x86/crash_dump_32: Use the new interface copy_oldmem_page_buf Date: Fri, 3 Dec 2021 16:12:22 +0530 Message-Id: <20211203104231.17597-6-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211203104231.17597-1-amit.kachhap@arm.com> References: <20211203104231.17597-1-amit.kachhap@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The current interface copy_oldmem_page() passes user pointer without __user annotation and hence does unnecessary user/kernel pointer conversions during its implementation. Implement the interface copy_oldmem_page_buf() to avoid this issue. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86 Signed-off-by: Amit Daniel Kachhap --- arch/x86/kernel/crash_dump_32.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c index 5fcac46aaf6b..9932cd62ded1 100644 --- a/arch/x86/kernel/crash_dump_32.c +++ b/arch/x86/kernel/crash_dump_32.c @@ -30,20 +30,20 @@ static inline bool is_crashed_pfn_valid(unsigned long pfn) } /** - * copy_oldmem_page - copy one page from "oldmem" + * copy_oldmem_page_buf - copy one page from "oldmem" * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) + * @ubuf: target user memory pointer for the copy; use copy_to_user() if this + * pointer is not NULL + * @kbuf: target kernel memory pointer for the copy; use memcpy() if this + * pointer is not NULL * @csize: number of bytes to copy * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). * - * Copy a page from "oldmem". For this page, there might be no pte mapped - * in the current kernel. + * Copy a page from "oldmem" into the buffer pointed by either @ubuf or @kbuf. + * For this page, there might be no pte mapped in the current kernel. */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset) { void *vaddr; @@ -55,10 +55,10 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, vaddr = kmap_local_pfn(pfn); - if (!userbuf) { - memcpy(buf, vaddr + offset, csize); + if (!ubuf) { + memcpy(kbuf, vaddr + offset, csize); } else { - if (copy_to_user(buf, vaddr + offset, csize)) + if (copy_to_user(ubuf, vaddr + offset, csize)) csize = -EFAULT; }